Wide dynamic range electronic image recording and reproducing system

ABSTRACT

The electronic camera has an imaging device that images a subject with subject reflectance R (%) with a dynamic range wider than that at displaying or printing to acquire image data and a recording device that converts the image data acquired by the imaging device with a predetermined function and records the converted image data and the information on the function as digital values (digit). Therefore, a printed image with an automatically or manually corrected density can be obtained at the displaying or the printing.

This application is a Continuation of co-pending application Ser. No.12/191,797 filed on Aug. 14, 2008, which is a Divisional of applicationSer. No. 09/654,263 filed on Sep. 1, 2000 and for which priority isclaimed under 35 U.S.C. §120; and this application claims priority ofApplication No. JP11/248638 filed in Japan on Sep. 2, 1999 andApplication No. JP11-248639 filed in Japan on Sep. 2, 1999 under 35U.S.C. §119; the entire contents of all are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an electronic image recordingand reproducing system, and more particularly to an electronic imagerecording and reproducing system including an electronic camera and animage reproducing apparatus such as an image monitor and a printer, inwhich image recording is performed with a dynamic range that is widerthan that being required at reproducing (e.g., displaying or printing)of the image data, and exposure can be changed at the reproducing.

2. Description of Related Art

Japanese Patent Provisional Publication No. 7-288738 discloses anautomatic exposure apparatus of an electronic camera that changeslatitudes according to scenes at imaging. The automatic exposureapparatus performs knee control that prevents saturation athigh-luminance parts in order to address a problem that thehigh-luminance parts are saturated since a luminance range is wide whena main subject is exposed at a normal exposure value with back light ortoo much front light.

The automatic exposure apparatus in Japanese Patent ProvisionalPublication No. 7-288738, however, can not perfectly match the exposureto any scenes since the automatic exposure apparatus only changes theluminance range by a knee processing. Saturation at highlight parts isprevented by the knee processing, but the highlight parts losedefinition and the image lacks in contrast. Also, over-exposure of amain subject can not be corrected at printing.

Japanese Patent Provisional Publication No. 11-69179 discloses an imagereproducing method in which image data of a range wider than the dynamicrange of the image reproducing apparatus is obtained; a density rangeappropriate for a reproduced image is found as setup information; andwhen an image file stored in an image information recording medium withthe image data is displayed, the user checks the displayed imageaccording to the setup information with a special software and choosesone piece of the setup information to display the image.

According to the image reproducing method in Japanese Patent ProvisionalPublication No. 11-69179, an image capturing operation is inconvenientlycomplicated, since it is required to predetermine the density range tobe actually reproduced in the printing within the captured imageinformation and to store the predetermined density range into the imagefile as a density range option. Moreover, the printing cannot always beperformed with the optimum density, since the density information shouldbe chosen in the reproducing from only the predetermined density range.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the above-describedcircumstances, and has as its object the provision of an electroniccamera in which imaging can be performed with a dynamic range that iswider than that required at displaying or printing of image data and aprinted image with automatically or manually corrected density can beobtained at the displaying or the printing.

To achieve the above-described object, the present invention is directedto an electronic camera comprising: an imaging device which images asubject so as to acquire image data with an imaging luminance rangewider than a reproducing luminance range on at least one of displayingand printing; and a recording device which converts the image dataacquired by the imaging device with a predetermined function and recordsthe converted image data and information on the predetermined function.

According to the present invention, the electronic camera has theimaging device that images the subject with the dynamic range wider thanthat at the displaying or the printing to acquire the image data and therecording device that converts the image data acquired by the imagingdevice with a predetermined function and records the converted imagedata and the information on the function. Therefore, the printed imagewith the automatically or manually corrected density can be obtained atthe displaying or the printing.

To achieve the above-described object, the present invention is directedto an image reproducing apparatus which reproduces a visible image by atleast one of displaying and printing according to first image datarecorded with a recording luminance range wider than a reproducingluminance range on the at least one of displaying and printing, theimage reproducing apparatus comprising: a reading device which reads thefirst image data with the recording luminance range and reads luminancerange information relating at least the recording luminance range; asignal processing device which produces, from the first image data withthe recording luminance range, second image data with a luminance rangerequired on the reproducing according to the luminance rangeinformation; and a reproducing device comprising at least one of: adisplaying device which displays the second image data as the visibleimage; and a printer which prints the second image data as the visibleimage.

To achieve the above-described object, the present invention is directedto an electronic image recording and reproducing system, comprising: animaging device which images a subject so as to acquire imaged data witha recording luminance range wider than a reproducing luminance range onat least one of displaying and printing; a recording device whichconverts the imaged data acquired by the imaging device with apredetermined function into a first image data and records the firstimage data and luminance range information relating at least thepredetermined function; a reading device which reads the first imagedata with the recording luminance range and reads the luminance rangeinformation; a signal processing device which produces, from the firstimage data with the recording luminance range, second image data with aluminance range required on the reproducing according to the luminancerange information; and a reproducing device comprising at least one of:a displaying device which displays the second image data as the visibleimage; and a printer which prints the second image data as the visibleimage.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature of this invention, as well as other objects and advantagesthereof, will be explained in the following with reference to theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures and wherein:

FIG. 1 is a block diagram showing the structure of a wide dynamic rangeelectronic image recording and reproducing system according to anembodiment of the present invention;

FIG. 2 is a graph diagram showing the relationship between subjectreflectance R (%) and a digital value to be recorded D (digit);

FIG. 3 is a graph diagram showing luminance correction in case therelationship between the subject reflectance R (%) and the digital valueto be recorded D (digit) is shown by a linear function;

FIG. 4 is a graph diagram showing luminance correction in case therelationship between the subject reflectance R (%) and the digital valueto be recorded D (digit) is shown by a logarithmic function;

FIG. 5 is a diagram showing the structure of the image file includingthe luminance information on the gradation conversion according to thepresent invention;

FIG. 6 is a flowchart showing a procedure for reading out the image filerecorded in a recording device and printing the image;

FIG. 7 is a graph diagram showing the relationship between the data atthe shooting, gradation conversion, gradation inverse conversion, andthe reproducing; and

FIG. 8 is a diagram showing a directory structure when the image file isrecorded in a recording device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereunder the preferred embodiment of the present invention is explainedin detail according to the accompanying drawings.

FIG. 1 is a block diagram showing the structure of a wide dynamic rangeelectronic image recording and reproducing system according to anembodiment of the present invention.

As shown in FIG. 1, an imaging part of an electronic camera 10 comprisesa lens group 16 that forms an image of a subject 12 on a solid-stateimaging device or a CCD 14, a diaphragm 18 that adjusts an amount oflight reaching the CCD 14, a diaphragm driving part 20 that adjusts theaperture of the diaphragm 18, a lens driving part 22 that adjusts theposition where the image of the subject is formed on the CCD 14, a CPU24 that performs control of the whole electronic camera 10, for example,control of the lens driving part 22, control of the diaphragm drivingpart 20 and setting of imaging timing signals, the CCD 14, a CDS 26 thatobtains R, G, B, G voltages corresponding to amounts of light byamplifying imaging signals and performing correlation double sampling ofthe imaging signals, an A/D converter 28 that converts analog imagesignals into digital signals, a timing generator 30 that transmitstiming signals synchronizing the CCD 14, the CDS 26 and the A/Dconverter 28 and controlling a reduction rate, a frame rate and a pixelnumber of image data and a recording mode switching device 31 thatswitches between a normal recording mode and a wide dynamic rangerecording mode.

An integrating circuit 32 has a TTL AE function of abstracting luminancecomponents from the obtained R, G, B, G digital signal values andfinding a luminance level of the subject by, for example, integratingthe digital signal values for a predetermined area and finding anexposure (an F-number and a shutter speed) and a contrast AF function ofmoving the lens group 16 so that, for example, high-frequency componentsof the image signals are maximum.

A signal processing part of the electronic camera 10 is provided with amemory 40 that temporarily stores the digitized R, G, B, G image dataoutputted in real time during the image signal processing at latterparts, a gamma correcting part 34 that performs gamma correction,optical black correction and white balance correction of the image data,an interline processing part 36 that produces R, G, B image data fromthe R, G, B, G image data and a YC converting part 38 that YC-convertsthe R, G, B image data into luminance information and color-differencesignals.

When the image is to be displayed by a displaying device 42 in the NTSCformat, an NTSC encoder 44 converts the YC-converted image data intovideo signals in the NTSC format.

When image data is to be recorded in a recording device 46, acompressing and expanding device 48 compresses the YC-converted imagedata and expands the compressed data at image data reading.

The electronic camera 10 further comprises a gradation converting device50 that performs gradation conversion such as logarithmic conversion ofthe luminance of the image at a wide dynamic range recording, acompressing device 52 that compresses the gradation-converted image dataand a signal processing part 54 that expands the compressed data or theimage data read from the recording device 46 and performs gradationinverse-conversion to produce second image data and performs gammacorrection and YC conversion to produce image to be displayed as needarises. The signal processing part 54 has a density adjusting devicethat can automatically or manually adjust density of a visible image.

A printer interface (I/F) 58 that controls a printer 56 and receives theobtained image data of the image to be printed from the compressing andexpanding device 48 or the signal processing part 54 and transmits theimage data to the printer 56.

Normal imaging of the electronic camera 10 constructed as describedabove that is different from wide dynamic range imaging will now beexplained.

When the user operates the recording mode switching device 31 to choosethe normal recording mode, a subject image formed on the CCD 14 throughthe lens group 16 is converted into electric charges by photoelectrictransferring devices of the CCD 14. The accumulated electric charges areoutputted from the CCD 14 according to an instruction of the timinggenerator 30 at fixed intervals.

The electric charges outputted from the CCD 14 are converted into thesignals of R, G, B, and G filter arrangement that correspond to thelight amounts by the CDS 26. The R, G, B, G analog signals are convertedinto the digital signals by the A/D converter 28 and are temporarilystored in the memory 40. After that, the digital signals aresequentially read out for the gamma correction, the optical blackcorrection, the white balance correction, the interline processing andYC conversion, and then the image is displayed by the displaying device42.

Then, the user turns the electronic camera 10 to the subject 12, andpresses a shutter release button (not shown) to perform a shooting afterdetermining the camera angle, the focus and the exposure with the manualor automatic with the AE function while looking at the image displayedby the displaying device 42.

The data of the image displayed by the displaying device 42 is recordedin the recording device 46 with a preset frame rate and pixel number forrecording.

Gradation converting and image data recording in the wide dynamic rangeimaging will now be explained.

When the user operates the recording mode switching device 31 to choosethe wide dynamic range recording mode and presses the shutter releasebutton while looking at the image displayed by the displaying device 42,the R, G, B, G digital luminance signals outputted from the A/Dconverter 28 are temporarily stored in the memory 40. After that, thedigital luminance signals are sequentially read out and transmitted tothe gradation converting device 50. The gradation conversion isperformed to produce first image data instead of the gamma correction,the interline processing and the YC conversion before the first imagedata is recorded in the recording device 46, so that a print of highquality can be acquired since a printer generally performs a printingaccording to R, G, B signals. The gradation converting processing of thegradation converting device 50 will now be explained with reference toFIGS. 2, 3 and 4.

FIG. 2 is a graph diagram showing the relationship between subjectreflectance R (%) and a digital value of the first image data to berecorded D (digit).

As shown in FIG. 2, subject reflectance of 200% conventionallycorresponds to a CCD output voltage corresponding to the maximum digitalvalue. In case of recording method with a 12-bit gradation, the AE isadjusted so that the digital value corresponding to the light amount(luminance) with subject reflectance of 200% is 4095 (12 bit). However,if subject reflectances largely differ from each other on one image, forexample, a subject with a half tone at a shooting is white or black onthe reproducing (e.g., displaying and printing) and the half tonedisappears since exposure values are often about 1.5 higher or lowerthan desired exposure values.

In the present invention, gains of the image data is changed so thatsubject reflectance of 700% corresponds to the CCD output voltagecorresponding to the maximum digital value to record the image data witha dynamic range that is much wider than that at the reproducing such asthe displaying and the printing. In case of the recording method withthe 12-bit gradation, the light amount with subject reflectance of 700%is 4095 (12 bit).

The dynamic range at the recording is two or more times as wide as thedynamic range at the reproducing such as the displaying and theprinting, so that the luminance equivalent to the subject reflectance R(%) can be corrected at the reproducing. Since the exposure values arenever higher or lower by 2.5 or more than desired exposure values andthe dynamic range of the CCD is limited, the recording dynamic rangedoes not have to be more than six times as wide as the reproducingdynamic range. Thus, the density of the visible image does not have tobe adjusted within a range that is wider than a range of ±2.5 EV.

FIG. 3 is a graph diagram showing luminance correction in case therelationship between the subject reflectance R (%) and the digital valueto be recorded D (digit) is shown by a linear function.

In FIG. 3, a straight line shows that the subject reflectance R withinthe range of 700% or lower can be recorded with the 12-bit gradationwith normal exposure. If the reproduced image is 1 EV darker than thedesired subject image due to incorrect photometry of the AE, a gain(gradient of the straight line in FIG. 3) is changed at the displayingor the printing to positively correct the exposure by 1 EV, so that thedesired subject image can be obtained. Though only the subjectreflectance R within the range of 350% or lower can be dealt with at thedisplaying, it does not matter at all for the following reasons.

A dynamic range at a printing is described in “Television SocietyJournal Vol. 47, No. 10, pp. 1395-1397 (1993) Japan” giving reversalfilm as an example. A photo CD described in the journal can deal withreflectance of 200% or lower, and the maximum reflectance of the dynamicrange at the actual displaying or the printing is 200%.

There is no problem since the maximum subject reflectance R of 350% incase of the positive exposure correction by 1 EV at the displaying orthe printing is much higher than the maximum reflectance of 200% of thedynamic range at the printing. Even if the exposure is positivelycorrected by 2 EV, the incorrect photometry of the AE can be completelycompensated for at the displaying or the printing when the subjectreflectance R within the range of 700% or lower is recorded since thesubject reflectance R within the range of 175% or lower can be dealtwith at the displaying. If the subject reflectance R is negativelycorrected, the incorrect photometry of the AE can be completelycompensated for since the dynamic range does not get narrower.

In the gradation conversion in which the relationship between thesubject reflectance R (%) and the digital value to be recorded D (digit)is shown by the linear function, an operation for the gradationconversion is easy at the recording, displaying or the printing, and itdoes not affect the processing speed.

The gradation-converted image data as described above is compressed asneed arises and recorded in the recording device 46.

By having both the conventional displaying method and the wide dynamicrange recording, the electronic camera 10 can display the subject imageon the displaying device at the shooting like the conventionalelectronic camera.

FIG. 4 is a graph diagram showing luminance correction in case therelationship between the subject reflectance R (%) and the digital valueto be recorded D (digit) is shown by a logarithmic function.

In FIG. 4, a line shows that the subject reflectance R within the rangeof 700% or lower can be logarithm-recorded with the 12-bit gradationwith the normal exposure. Logarithmic recording conversion is shown bythe following equations 1 and 2;D0=1500×log₁₀ R−172(2.805≦R)  equation 1, andD0=R×500/2.805(2.805≧R)  equation 2,

where D0 is a logarithm recording value (digit) at a shooting with thenormal exposure and R is the subject reflectance (%). The bases of thelogarithms are 10 in the equations, but the present invention is notlimited to this.

In the logarithm recording, the subject reflection R is recorded withstraight lines instead of being logarithm-converted when the digitalvalue D is 500 or lower (2.805≧R) so that resolution when the reflectionis low is kept high and the digital value D is 0 when the subjectreflection R is 0.

The subject reflection R is logarithm-recorded as described above, andthus the resolution when the reflection is low can be kept high and thewide dynamic range recording can be performed. The operation for thegradation conversion in the electronic camera is more complicated thanthat in the recording method with the linear function, but the exposurecorrection is easy since the data only needs to be shifted (difference)when the exposure is corrected at the displaying or the printing.

Logarithmic recording conversion when the camera positively corrects theexposure by 1 EV is shown by the following equations 3 and 4, andlogarithmic recording conversion when the camera positively corrects theexposure by 2 EV is shown by the following equations 5 and 6, andlogarithmic recording conversion when the camera negatively corrects theexposure by 1 EV is shown by the following equations 7 and 8;D1=1500×log₁₀ R+280(1.401≦R)  equation 3,D1=R×500/1.401(1.401≧R)  equation 4,D2=1500×log₁₀ R+732(0.7≦R)  equation 5,D2=R×500/0.7(0.7≧R)  equation 6,D3=1500×log₁₀ R−624(5.615≦R)  equation 7, andD3=R×500/5.615(5.615≧R)  equation 8,

where D1 is a logarithm recording value (digit) at the positive exposurecorrection by 1 EV, and D2 is a logarithm recording value (digit) at thepositive exposure correction by 2 EV, and D3 is a logarithm recordingvalue (digit) at the negative exposure correction by 1 EV.

The gradation-converted first image data as described above iscompressed as need arises and recorded in the recording device 46. Thedata of the recorded image file has conventionally a gradation differentfrom that of the image at the shooting when it is read out and displayedor printed. To address this problem, a tag including luminanceinformation showing the gradation of the image file has been convertedis recorded with the image file, and the gradation is converted within acorrection-possible range according to the tag at the displaying or theprinting to produce the second image data.

FIG. 5 is a diagram showing the structure of the image file includingthe luminance information on the gradation conversion according to thepresent invention.

As shown in FIG. 5, the image file 70 comprises tag information of theimage file and an image data area 82 in which the image data isrecorded, and the tag information includes wide dynamic range recordinginformation 72 showing whether the image data was recorded with the widedynamic range, dynamic range information 74 showing maximum reflectanceinformation that has been actually set in the camera, recorded gradationstate 76 that is converting equations, first-order and zero-orderconstants and the format, compression form 78 that is informationshowing whether the image data has been compressed and the from of thecompression, filter arrangement form 80 that is information showing thefilter structure for separating the output from the CCD 14 into R, G andB signals, and so on.

The tag information in the gradation recording method is recorded in theheader part of the image file 70 as described above, and thus the imageat the shooting can be faithfully reproduced.

FIG. 6 is a flowchart showing a procedure for reading out the image filerecorded in the recording device 46 and printing the image.

After the image file 70 to be printed is read out of the recordingdevice 46 and the processing for converting the image data in the imagefile 70 into the print image is started, the processing program goes toS100 of “DETERMINE WHETHER IMAGE DATA HAS BEEN RECORDED WITH WIDEDYNAMIC RANGE” in FIG. 6.

At S100, the wide dynamic range recording information 72 recorded in theheader part of the image file 70 is read and it is determined whether ornot the image data has been recorded with the wide dynamic range. Ifyes, the signal processing part 54 in FIG. 1 processes the data of theread image file in the wide dynamic range processing in FIG. 6. If theimage data has been recorded in the normal recording method, thecompressing device 48 in FIG. 1 performs conventional expansion anddevelopment processing.

At S102 of “DETERMINE RECORDED GRADATION METHOD,” the recorded gradationstate 76 of the tag information is read and the converting equations andthe constants of the gradation conversion and the method of developingthe image data according to the form are set.

At S104 of “DETERMINE RECORDED DYNAMIC RANGE,” the dynamic rangeinformation 74 showing maximum reflectance information that has beenactually set in the camera is read from the tag information and set as aconstant at the gradation conversion.

At S106 of “DETERMINE COMPRESSION METHOD,” the compression form 78 isread from the tag information and a constant for developing the imagedata is set according to the information showing whether the image datahas been compressed and the from of the compression.

At S108 of “DETERMINE FILTER ARRANGEMENT,” the filter arrangement form80 is read from the tag information and the interline processing is setaccording to the filter arrangement of the CCD 14.

At S110 of “EXPANSION,” the image data recorded in the image data area82 according to the information of the compression form 78 is expanded.

At S112 of “INTERLINE PROCESSING,” the interline processing is performedaccording to the filter arrangement of the CCD 14 to separate the imagedata into the R, G and B image data.

At S114 of “EXPOSURE CORRECTION,” the exposure of the separated imagedata is automatically corrected.

At S116 of “COLOR CORRECTION,” the white balance of theexposure-corrected image data is corrected, and then the corrected imagedata is YC-converted and displayed on the displaying device 42 throughthe NTSC encoder 44 in FIG. 44.

At S118 of “EXPOSURE CORRECTION” and S120 of “COLOR CORRECTION,” theuser determines whether or not exposure correction and color correctionare needed while looking at the image displayed on the displaying device42, and the user determines correction amounts and performs them if theyare needed. The correction amounts for the exposure correction and thecolor correction are determined according to the dynamic rangeinformation 74 of the tag information. The image data is correctedaccording to the determined correction amounts and thegradation-inverse-conversed image is displayed on the displaying device42.

At the printing, the gamma correction suitable for the printing isperformed at S122 of “GAMMA CORRECTION” as need arises.

At S124 of “INCREASE OR DECREASE NUMBER OF PIXELS,” the number of thepixels is changed according to the definition of the print. At S126 of“SHARPNESS PROCESSING,” sharpness processing is performed for edges ofthe image. After various corrections, the image data is transmitted tothe printer 56 through the printer I/F 58 and the printing is performedat S128 of “PRINTING.”

The image data recorded with the wide dynamic range is reproduced orprinted in the above-described way, and thus the print whose density isappropriate can be obtained even if the AE was incorrect at theshooting.

It is easy for the user to shoot when the diaphragm 18 is relativelysmall and the shooting timing, which corresponds to the shutter speed,is high (exposure amount is small), and thus the exposure is low byabout 1 EV-2 EV dark at the wide dynamic range imaging and it can becorrected at the printing. If the normal imaging mode is 200% imagingand the wide dynamic range imaging mode is 700% imaging and the exposurevalue in the normal imaging mode is 12, the exposure is under and thecorrection value is log₁₀(700/200)/log₁₀2=1.8 EV and the exposure valueis 13.8.

At the wide dynamic range imaging, the imaging in the normal imagingmode may be performed at the same time. In this case, the imaging isperformed with the exposure value and the gain of the data of the normalimaging mode is increased by a gain controlling device (not shown)before the gamma correction part 34, and the image data with theexposure value of the normal imaging mode.

FIG. 7 is a graph diagram showing the relationship between the data atthe shooting, gradation conversion, gradation inverse conversion, andthe displaying or the printing.

The gradation conversion at the shooting and the printing will now beexplained.

If the AE of the electronic camera 10 matches the desired exposure forthe subject with subject reflectance R1 in the fourth quadrant, theimage with the subject reflectance R1 is converted into the digitalvalue to be recorded of a point K2 through a point K1 on a logarithmicgradation conversion curved line of the normal exposure, and the imageis recorded in the recording device 46.

If the recorded image is to be reproduced, the recorded digital value ofthe point K2 is converted into the displaying or printing digital valueof a point K4 through a point K3 on a logarithmic gradation inverseconversion curved line of the normal exposure in the third quadrant.Then, the displaying or printing digital value of the point K4 isconverted into the displaying or printing density of a point K6 througha point K5 on a displaying or printing characteristic curved line in thesecond quadrant.

If the AE of the electronic camera 10 sets the exposure that is 1 EVlower than the desired exposure, the diaphragm 18 is larger for 1 EV andthe subject with the subject reflectance R1 is recorded with the digitalvalue to be recorded of a point K12. The digital value to be recorded ofthe point K12 is converted into the printing digital value of a pointK14 through a point K13 on the logarithmic gradation inverse conversioncurved line of the normal exposure. When the image data is reproduced,the printing digital value of the point K14 is converted into thedisplaying or printing digital value of a point K16 through a point K15on the displaying or printing characteristic curved line in the secondquadrant, and thus the density of the reproduced image is lower thanthat of the subject for 1 EV and the image is too light.

The user chooses a logarithmic gradation inverse conversion curved linefor positive exposure correction of 1 EV in the third quadrant andconverts the digital value to be recorded of the point K12 into thedisplaying or printing value of a point K4 through a point K17 on thelogarithmic gradation inverse conversion curved line for positiveexposure correction of 1 EV to perform positive exposure correction of 1EV while looking at the reproduced image that is lighter than thedesired image. The displaying or printing value of the point K4 isconverted into the displaying or printing density of a point K5 on thedisplaying or printing characteristic curved line in the secondquadrant.

If the AE of the electronic camera 10 sets the exposure that is 1 EVhigher than the desired exposure, the diaphragm 18 is smaller for 1 EVand the subject with the subject reflectance R1 is recorded with thedigital value to be recorded of a point K22. The digital value to berecorded of the point K22 is converted into the printing digital valueof a point K24 through a point K23 on the logarithmic gradation inverseconversion curved line of the normal exposure. When the image data isreproduced, the printing digital value of the point K24 is convertedinto the displaying or printing digital value of a point K26 through apoint K25 on the displaying or printing characteristic curved line inthe second quadrant, and thus the density of the reproduced image ishigher than that of the subject for 1 EV and the image is too dark.

The user chooses a logarithmic gradation inverse conversion curved linefor negative exposure correction of 1 EV in the third quadrant andconverts the digital value to be recorded of the point K22 into thedisplaying or printing value of the point K4 through a point K27 on thelogarithmic gradation inverse conversion curved line for negativeexposure correction of 1 EV to perform negative exposure correction of 1EV while looking at the reproduced image that is darker than the desiredimage. The displaying or printing value of the point K4 is convertedinto the displaying or printing density of the point K5 on thedisplaying or printing characteristic curved line in the secondquadrant.

In the above explanation, the user manually corrects the density whilelooking at the reproduced image, but the density of the image may beautomatically determined and corrected.

A conversion curved line in the first quadrant in FIG. 7 shows theprocessing in the second, third and fourth quadrants. The subject withthe subject reflectance R1 in the first quadrant is converted into theprint density of the point K6 through a point K7 on the curved line, andthe image is recorded in the recording device 46 with the print densityof the point K6.

FIG. 8 shows the directory structure when the image file is recorded inthe recording device 46.

As shown in FIG. 8, a directory named “DCIM” is composed of a directory“Widerange” storing image files recorded with the wide dynamic range anda directory “NomalRange” storing image files recorded in the normalmode.

The directory “Widerange” stores image files “Dscw0001.tif,”“Dscw0002.tif,” recorded with the wide dynamic range. “Dscw” representsthat the image files have been recorded with the wide dynamic range.“0001” represents the shooting order or the type, and the extension“tif” represents the structure of the compressed file.

The directory “NomalRange” stores image files “Dscn0001.jpg,”“Dscn0002.jpg,” . . . recorded in the normal imaging mode. “Dscn”represents that the image files have been recorded in the normal imagingmode. “0001” represents the shooting order or the type, and theextension “jpg” represents the structure of the compressed file.

The image files recorded with the wide dynamic range and the image filesrecorded in the normal imaging mode are classified with the directoriesand the file names as described above, and thus the image files can beeasily arranged, classified and searched after shooting.

As explained above, the electronic camera according to the presentinvention has the imaging device that images the subject with thedynamic range wider than that at the displaying or the printing toacquire the image data and the recording device that converts the imagedata acquired by the imaging device with a predetermined function andrecords the converted image data and the information on the function.Therefore, the printed image with the automatically or manuallycorrected density can be obtained at the displaying or the printing.

It should be understood, however, that there is no intention to limitthe invention to the specific forms disclosed, but on the contrary, theinvention is to cover all modifications, alternate constructions andequivalents falling within the spirit and scope of the invention asexpressed in the appended claims.

What is claimed is:
 1. An electronic camera, comprising: an imagingdevice configured to image a subject to acquire a piece of image data,the imaging device configured to perform a normal imaging in which theimaging device images the subject in a first dynamic range, and toperform a wide dynamic range imaging without an image combining processin which the imaging device images the subject in a second dynamic rangewhich is wider than the first dynamic range to acquire a piece of widedynamic range image data by imaging the subject with an exposure valuethat is lower than an exposure value for normal imaging, wherein thefirst dynamic range corresponds to a reproducing dynamic range used forat least one of displaying and printing; and a recording deviceconfigured to record the acquired image data the recording deviceconfigured to record an information indicating that the piece of widedynamic range image data which is directly acquired in the wide dynamicrange imaging is imaged in the second dynamic range along with the pieceof wide dynamic range image data.
 2. The electronic camera according toclaim 1, wherein the imagine device images the subject with a firstexposure value obtained from normal photometry in the normal imaging;and the imaging device images the subject with a second exposure valuelower than the first exposure value in die wide dynamic range imaging.3. The electronic camera according to claim 1, wherein the recordingdevice records a piece of image data acquired in the normal imaging anda piece of image data acquired in die wide dynamic range imaging so thatthey are classifiable with each other.
 4. The electronic cameraaccording to claim 1, wherein the recording device records a piece ofimage data acquired in the normal imaging in a first directory and apiece of image data acquired in the wide dynamic range imaging in asecond directory.
 5. The electronic, camera according to claim 1,wherein the recording device records a piece of image data acquired inthe normal imaging and a piece of image data acquired in the widedynamic range imaging so that they are classifiable with each other bytheir filenames.
 6. The electronic camera according to claim 1, whereinthe recording device records the acquired image, the recording deviceconfigured to record a piece of normal image data acquired in the normalimaging and the piece of wide dynamic range image data.
 7. Theelectronic camera according to claim 1, further comprising: a modeswitching device configured to switch an imaging mode of the electroniccamera between a normal imaging mode in which the imaging device imagesthe subject in the first dynamic range and a wide dynamic range imagingmode in which the imaging device images the subject in the seconddynamic range.
 8. The electronic camera according to claim 7, wherein,when the imaging mode of the electronic camera is in the wide dynamicrange imaging mode, the imaging device performs both the normal imagingand the wide dynamic range imaging, and the recording device recordspieces of image data acquired by both the normal imaging and the widedynamic range imaging.
 9. An electronic camera, comprising: an imagingdevice configured to image a subject to acquire a piece of image data,the imaging device configured to perform a normal imaging in which theimaging device images the subject in a first dynamic range to acquire apiece of normal image data, and to perform a wide dynamic range imagingin which the imaging device images the subject in a second dynamic rangewhich is wider than the first dynamic range to acquire a piece of widedynamic image data by imaging the subject with an with an exposure valuethat is lower than an exposure value for normal imaging, wherein thefirst dynamic range corresponds to a reproducing dynamic range used forat least one of displaying and printing; and a recording deviceconfigured to record the piece of wide dynamic image data acquired bythe wide dynamic range imaging with the piece of normal image data. 10.The electronic camera according to claim 9, wherein the recording devicerecords an information indicating that the piece of wide dynamic rangeimage data acquired in the wide dynamic range imaging is imaged in thesecond dynamic range along with the piece of wide dynamic range imagedata.